Encyclopedia of Geomagnetism and Paleomagnetism

2007 Edition
| Editors: David Gubbins, Emilio Herrero-Bervera

Nondipole Field

  • Catherine Constable
Reference work entry
DOI: https://doi.org/10.1007/978-1-4020-4423-6_221
The nondipole (ND) field is that part of the internal geomagnetic field remaining after the major geocentric dipole contribution has been removed. It is distinct from the nonaxial‐dipole (NAD) field for which only the component of the geocentric dipole that is parallel to Earth's rotation axis is subtracted. Figure N4a/Plate 4a shows the strength of the total scalar field at Earth's surface, with the spatial variations dominated by the dipole field, while in Figure N4b/Plate 4b the dipole contribution has been subtracted to reveal the substantially more complex nondipole field. Two source regions contribute to the ND field: the dynamo in Earth's core that is also responsible for the dipole part of the geomagnetic field produces the largest part; the other source is Earth's lithosphere (see  Crustal magnetic field). Nondipole field contributions are significant, but contribute only a small fraction of the average magnetic energy at the surface, as can be seen in Figure N5a, which shows O...
This is a preview of subscription content, log in to check access

Bibliography

  1. Bloxham, J., Gubbins, D., and Jackson, A., 1989. Geomagnetic secular variation. Philosophical Transactions of the Royal Society of London, Series A, 329: 415–502.CrossRefGoogle Scholar
  2. Courtillot, V., and Besse, J., 2004. A long‐term octupolar component in the geomagnetic field. In Channell, J.E.T., Kent, D.V., Lowrie, W., and Meert, J.G. Timescales of the Paleomagnetic Field, AGU Geophysical Monograph 145. Washington, DC: American Geophysical Union, pp. 59–74.Google Scholar
  3. Dunlop, D.J., and Yu, Y., 2004. Intensity and polarity of the geomagnetic field during Precambrian time. In Channell, J.E.T., Kent, D.V., Lowrie, W., and Meert, J.G. (eds.), Timescales of the Paleomagnetic Field, AGU Geophysical Monograph 145. Washington, DC: American Geophysical Union, pp. 85–100.Google Scholar
  4. Gubbins, D.G., 1998. Interpreting the paleomagnetic field. In Gurnis, M. The Core‐Mantle Boundary Region. Washington, DC: AGU Geodynamics Series 28, pp. 167–182.Google Scholar
  5. Gubbins, D.G., 2003. Thermal core‐mantle interactions. In Dehant, V., Creager, K.C., Karato, S., and Zatman, S. (eds.), Earth's Core: Dynamics, Structure, Rotation, AGU Geodynamics Series 31. Washington, DC: American Geophysical Union, pp. 163–179.Google Scholar
  6. Gubbins, D.G., and Gibbons, S.J., 2004. Low Pacific secular variation. In Channell, J.E.T., Kent, D.V., Lowrie, W., and Meert, J.G. (eds.), Timescales of the Paleomagnetic Field, AGU Geophysical Monograph 145. Washington, DC: American Geophysical Union, pp. 279–286.Google Scholar
  7. Jackson, A., Jonkers, A.R.T., and Walker, M.R., 2000. Four centuries of geomagnetic secular variation from historical records. Philosophical Transactions of the Royal Society of London, Series A, 358: 957–990.CrossRefGoogle Scholar
  8. Jault, D., 2003. Electromagnetic and topographic coupling, and LOD variations. In Jones, C., Soward, A., and Zhang, K. (eds.), Earth's Core and Lower Mantle. The Fluid Mechanics of Astrophysics and Geophysics. London: Taylor & Francis, pp. 56–76.Google Scholar
  9. Johnson, C.L., and Constable, C.G., 1997. The time‐averaged geomagnetic field: global and regional biases for 0–5 Ma. Geophysical Journal International, 131: 643–666.CrossRefGoogle Scholar
  10. Korte, M., and Constable, C.G., 2005. Continuous geomagnetic models for the past 7 millennia II: CALS7K. Geochemistry, Geophysics, Geosystems, 6(2): Q02H16 DOI 10.1029/2004GC000801.Google Scholar
  11. McElhinny, M.W., 2004. Geocentric axial dipole hypothesis: a least squares perspective. In Channell, J.E.T., Kent, D.V., Lowrie, W., and Meert, J.G. (eds.), Timescales of the Paleomagnetic Field, AGU Geophysical Monograph 145. Washington, DC: American Geophysical Union, pp. 1–12.Google Scholar
  12. Merrill, R.T., McElhinny, M.W., and McFadden, P.L., 1996. The Magnetic Field of the Earth: Paleomagnetism, the Core and the Deep Mantle. San Diego, CA: Academic Press.Google Scholar
  13. Olsen, N., 2002. A model of the geomagnetic field and its secular variation for epoch 2000. Geophysical Journal International, 149: 454–462.CrossRefGoogle Scholar
  14. Van der Voo, R., and Torsvik, T., 2004. The quality of the European Permo‐Triassic paleopoles and its impact in Pangea reconstructions. In Channell, J.E.T., Kent, D.V., Lowrie, W., and Meert, J.G. (eds.), Timescales of the Paleomagnetic Field, AGU Geophysical Monograph 145. Washington, DC: American Geophysical Union, pp. 29–42.Google Scholar

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Catherine Constable

There are no affiliations available